Pollen-derived microcapsules for aspirin microencapsulation: in vitro release and physico-chemical studies

Natural sporopollenin microcarriers: Morphological insights into their functional performance for drug encapsulation and release

Natural sporopollenin microcapsules (SMCs) derived from pollen offer versatility and efficiency for different applications, from environmental remediation to food and therapeutics delivery. A critical gap remains in understanding the relationship between SMCs morphologies and their effectiveness in drug loading and delivery. Herein, we encapsulated 5-Fluorouracil (5-FU), a model anticancer drug, into SMCs derived from seven bee monofloral pollens, each exhibiting distinct morphological features, and examined how their loading and release performance correlated with their morphology. Microscopic and particle size analyses revealed that the chemically purified SMCs were hollow, with sizes ranging from 11.0 to 35.6 μm, without significant size changes after drug loading. Encapsulation efficiency achieved through vacuum-assisted loading (18-28 %) generally surpassed that of passive and compression loading techniques. Moreover, there was a trend of increasing encapsulation efficiency with larger SMC sizes, albeit with some exceptions. In a sequential release environment simulating the in vitro gastrointestinal tract and colonic fermentation, smaller SMCs exhibited a faster release profile, whereas larger ones demonstrated a slower sustained release. The quantity and shape of apertures on SMCs walls significantly impacted their drug-loading capacity and release characteristics. Additionally, natural SMCs remained structurally intact even in the presence of digestive enzymes, varying pH levels, and colonic bacteria, indicating minimal degradation under these conditions. Overall, the findings highlight the significant influence of SMCs morphologies on their functional performance and provide a list of SMCs-based microstructures to guide drug release applications.

Fabrication of well-defined magnetic microporous polymeric monoliths using simple non-aqueous emulsification technique

The current work describes a novel route for preparation of robust polymeric monolithic structures exhibiting magnetic properties via emulsification of a polar glycerin oil in a polymerizable hydrophobic oil of styrene as oil/oil (o/o) emulsion technique. Hydrophilic magnetite nanoparticles were first prepared via the co-precipitation method and then converted to organophilic using oleic acid as a surface coating material. The FT-IR provided evidence on the covering of the particle's surface and also revealed some hydrophilic OH groups co-exist, implying a probable amphiphilic character is acquired. The organophilic particles act efficiently as Pickering stabilizers for glycerin/styrene emulsion systems. Styrene, a polymerizable oil, could be subsequently polymerized at 70 °C in the presence of an oil-soluble thermal initiator such as 1,1-azobiscyclohexanecarbonitrile (vazo). Scanning electron microscopy (SEM) confirmed the formation of well-defined, highly porous polymeric monoliths, in which the distribution of the pores within the monolith further supported that they were prepared via well-emulsified glycerin drops in the styrene phase as a precursor. Additionally, the EDX revealed the presence of the iron element distributed evenly within the monolith. The thermogravimetric analysis (TGA) revealed a slight resistance to thermal degradation over a narrow range up to 150 °C with respect to pure polystyrene, whereas beyond this temperature the degradation behavior proceeded almost typically as for pure polystyrene. The ferromagnetic resonance spectroscopy (FMR) indicated the acquisition of the magnetic property by the produced monolith structure. For the best of our knowledge, it is the first article of its type investigating the fabrication of polymeric monolithic structures from non-aqueous emulsions.

Controlled release of trifluralin herbicide using luminescent Vibrio-derived polyhydroxyalkanoate (PHA) microcapsules

The controlled release of herbicides using new and safe materials can mitigate environmental pollution. Polyhydroxyalkanoate (PHA) is a type of biopolymer that can be produced by various bacteria. It has properties that make it suitable for encapsulation and controlled release applications. A luminescent bacterium, Vibrio sp. VLC strain was used as the PHA producer in this study. Initially, the polymer was synthesized by the bacterium following optimization of the culture medium, resulting in an approximate yield of 25 %. Subsequently, the produced polymer was analyzed using TEM, FTIR, and H-NMR techniques. Microcapsules were produced using the emulsion method. FE-SEM imaging revealed spherical microcapsules with an average diameter of 0.5-2 μm. The herbicide loading content and encapsulation efficiency were determined to be 16.64 % and 66.56 %, respectively. The herbicidal effect of the microcapsules containing trifluralin was investigated using Amaranthus retroflexus and Setaria viridis plants, demonstrating a significant reduction in various parameters after application. Furthermore, the impact of encapsulated herbicide on soil microbial population was assessed, revealing a less negative effect compared to its free form. These findings suggest that the PHA from a luminescent vibrio holds promise as an eco-friendly, biodegradable, nontoxic material for the controlled release of herbicides.

Multifaceted roles of pollen in the management of cancer

Oral drug delivery of microparticles demonstrates shortcomings like aggregation, decreased loading capacity and batch-to-batch variation, which limits its scale-up. Later, porous structures gained attention because of their large surface-to-volume ratio, high loading capacity and ability to carry biomacromolecules, which undergo degradation in GIT. But there are pitfalls like non-uniform particle size distribution, the impact of porogen properties, and harsh chemicals. To circumvent these drawbacks, natural carriers like pollen are explored in drug delivery, which withstands harsh environments. This property helps to subdue the acid-sensitive drug in GIT. It shows uniform particle size distribution within the species. On the other side, they contain phytoconstituents like flavonoids and polysaccharides, which possess various pharmacological applications. Therefore, pollen has the capability as a carrier system and therapeutic agent. This review focuses on pollen's microstructure, composition and utility in cancer management. The extraction strategies, characterisation techniques and chemical structure of sporopollenin exine capsule, its use in the oral delivery of antineoplastic drugs, and emerging cancer treatments like photothermal therapy, immunotherapy and microrobots have been highlighted. We have mentioned a note on the anticancer activity of pollen extract. Further, we have summarised the regulatory perspective, bottlenecks and way forward associated with pollen.